Charging While Towing

SoundGuy wrote:

brulaz wrote:
So installed a left-over 1000W inverter in the truck (which has a 220A alternator). Good for other things too (like charging tool batteries), but primarily use it to run a 650W battery charger in the trailer. Added an extension cord with water tight couplings between truck and trailer and we're good.

Curious - did you install the inverter under the hood or elsewhere, how long is the run to the inverter input, what input cable gauge did you use, and did you connect directly to the starting battery or elsewhere? :@

Its in the bed of the truck on a shelf behind the cab and under the cap. Makes it easy to use for charging tools, as I can open the side door of the cap and get at it. Also I can see the display (it's one of the Cantire 1000W PSWs) from inside the Reg/Std cab.

Didn't want the hassle of putting it in the cab, and the fan noise may also have been an issue. It's a Reg/Std cab so space is at a premium and noise carries. (Still don't know how best to get big wires through the firewall.) And I didn't trust the heat and possible water in the engine compartment. Besides there's very little room there as well.

The wires are 6 awg with a 60A Maxi fuse and 140A (13.3V on, 12.8V off) Princess Auto isolator. The wire goes under the cab and being a Std/Reg cab it's ~15 ft. That 60A is all I need for the trailer's 500-700W charger, and tool charging.

The + and - wires comes off the truck's passenger side battery terminal (diesel truck with 2 batteries), on top of all the fuses and other wires there. The 220A alternator is close by with fat wires to the battery.

I never see less than 13V at the inverter, usually over 14V. There's definitely voltage drop and wasted energy but with that big alternator it doesn't really matter. But if I wanted to use the full 1000W of the inverter, I'd would have to go up in wire/fuse size or move the inverter into the cab or engine compartment. But for now it's all I need.